You also might want to tweak the settings in /etc/sysconfig/cpuspeed. I typically set the UP_THRESHOLD to 11 and the DOWN_THRESHOLD to 10 - would go lower but those seem to be hard coded limits. I also append -i 5 -r -n -w to OPTS and set IGNORE_NICE to 0 so background processes get the benefit of a faster CPU to get done as well.